What is a PDF file
PDF stands for Portable Document Format and was developed by Adobe. PDF files present a document in a fixed layout (much like an image) which translates the same throughout various programs, hardware, and operating systems. It allows the user to utilize various images, fonts, and text formats (sometimes search-able and containing hyperlinks) in a single document that is print-ready and easy to share from any device. Most PDF readers are royalty free for ease of access and use. These files can be password protected, encrypted, edited, and 3D artwork has been supported since 2004. To easily merge, rotate or edit PDF online, check out this free PDF editor. Any computer with Adobe Acrobat Reader (or similar product) can open a PDF file. Many mobile devices (phone and tablets) can view, send, and save the files as well.
PDF files have two different layouts: non-linear and linear. Non-linear (non optimized) files are smaller but slower to load because the data needed is scattered throughout the file. Linear (optimized) files can often be viewed in the web-browser and do not require the entire document to download before they can be viewed. A non-linear file may be optimized using Adobe Acrobat. PDF files do not encode the information needed for the application to run, meaning it only contains the data describing the document. PDF files can be made interactive by the use of rich media, annotations, flash animation, 3D art and 2D vector graphs, and attachments, as well as various security measures (encryption, digital signatures, etc). To open our example files, use the following password: online-convert.com In case of the "example_protected_userowner_nopermissions.pdf" file, the following is the owner password: online convert (incl. the whitespace)
Here's a small, but not exhaustive list of programs that can open PDF documents:
- Adobe Viewer
- Ghostscript
- Ghostview
- Xpdf
- gPDF
- Acrobat Reader
